• Want to add an app icon for this forum to your mobile device's home screen? Check out this thread to see how.
  • Have an event you want to share? Check out the new forum event calendar and how-to use it in this thread here.
  • To both new members and existing members, please read this thread about posting your topics in the correct sub-forum. It makes my job (and my life) a lot easier!

Is a stroker rebuild worth it?

Forty

TJ Enthusiast
Supporting Member
Nov 28, 2016
164
48383
Hey all,

It’s been a minute but I’m back after all kinds of home remodeling lol. So my 06 TJ with only 54k miles needs a rebuild :patadaenwevs:. Wow did I get taken on this Jeep!
I’ve got a good place in Highland, MI for the motor work I can’t do (machining etc.) but considering having a stroker kit installed vs standard. Obviously there will be a bit more power but is it worth the extra cost and what are the cons aside from worse gas mileage? :BangHead:
 

Chris

Administrator
Staff Member
Sep 28, 2015
37,235
Salem, Oregon
Maybe @Johnie Burns will chime in hear, I believe he's got a nice stroker build going on as we speak.

Why are you thinking it needs a rebuild with 54k miles? That's almost unheard of. Is the compression shot or something?

A stroker kit is worth it if done properly and for the right price. You probably will lose a little fuel economy, but only because your foot will be heavier on the pedal.
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
Hey all,

It’s been a minute but I’m back after all kinds of home remodeling lol. So my 06 TJ with only 54k miles needs a rebuild :patadaenwevs:. Wow did I get taken on this Jeep!
I’ve got a good place in Highland, MI for the motor work I can’t do (machining etc.) but considering having a stroker kit installed vs standard. Obviously there will be a bit more power but is it worth the extra cost and what are the cons aside from worse gas mileage? :BangHead:
Shorter engine life due to a long stroke, forced ability to run 91 octane, & you will want to gun it everywhere ;).
 
  • Like
Reactions: Forty

Mike_H

Rust Belt Heavyweight
Supporting Member
Feb 28, 2017
4,302
Grand Rapids, MI, United States
Shorter engine life due to a long stroke, forced ability to run 91 octane, & you will want to gun it everywhere ;).
Shorter engine lift due to long stroke? Says who? I don't think it has to be. They've been building strokers for a LONG time. Not just the 4.0, but the Chevy SBC too. You also don't need to run 91 Octane...That is a function of compression, not stroke.

I have a buddy running a stroker, around 4.6L, IIRC. Its in a Cherokee that he bought used from a guy he knows. Its got a bunch of miles on it. My friend has probably put 30k on it, and I don't know how long before he got it the engine work was done. Its actually the only part of the Cherokee worth a damn. It will push that truck down the highway at 75 mph all day long with 35's. He does have it geared to 4.88, I think. It runs great...and only needs 87 octane.
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
Shorter engine lift due to long stroke? Says who? I don't think it has to be. They've been building strokers for a LONG time. Not just the 4.0, but the Chevy SBC too. You also don't need to run 91 Octane...That is a function of compression, not stroke.

I have a buddy running a stroker, around 4.6L, IIRC. Its in a Cherokee that he bought used from a guy he knows. Its got a bunch of miles on it. My friend has probably put 30k on it, and I don't know how long before he got it the engine work was done. Its actually the only part of the Cherokee worth a damn. It will push that truck down the highway at 75 mph all day long with 35's. He does have it geared to 4.88, I think. It runs great...and only needs 87 octane.
Here is a post from another forum with quite a bit of informantion in it:

Axl Jack 02:01 AM 03-25-2010
I think the only regret somebody would have, if they bought a stroker from a certain re-manufacturer, is if their Jeep is their DD and now have to run higher octane fuel. (Read the fine print on a lot of websites.... says their stroker engines have to run on 92 octane because of the higher compression ratios.) So yeah you're getting a lot more power (and fun), but now not only are you getting worse gas mileage, but you have to fill it up with more expensive fuel!

Quote:
Originally Posted by wendell
JP mag says they haven't seen a stroker get over 20,000 miles on them.
Sometimes stroker's aren't as durable. Now, that's not to say, "Oh my God! A stroker will wear down after 10,000 miles." Let me explain. (Hmmmm, let me do some Googling here.)

Its mostly about rod ratio (rod to stroke ratio). Rod Ratio = (rod length / stroke) This little calculation tells you the motor's rod angularity. A LOW rod ratio means a HIGH rod angle. A high rod angle creates a greater potential for accelerated wear to cylinder walls, pistons, and piston rings (picture an extremely low rod ratio that is driving the piston into the side of the cylinder wall). For example, a motor with a 5.400" rod length and a 3.000" stroke yields a rod ratio of 1.8:1. If we maintain the same stroke and shorten the rod length to 5.000" we get a 1.7:1 rod ratio. The rod angle has increased.

The picture on the left is Low Rod Angle (or High Rod Ratio) and the picture on the right is High Rod Angle (or Low Rod Ratio). The bottom picture is just there as an extra visual aid.

rodangle.gif


129_0711_02_z+1987_2006_jeep_40l_inline_six+drawing.jpg


By lengthening the rod (as stroke is increased) you can offset the increased rod angle. But this requires further shortening of the piston. The further the piston is shortened the more likely the piston pin will intersect the oil ring groove, creating a potential for increased oil consumption.

Basically, there comes a point when you cannot shorten the piston any further before dependability is compromised.

The consensus, from what I've read, among engine manufacturers is that a ratio of 1.50" is the lowest acceptable rod ratio for a street motor. Realistically, rod ratios between 1.65 - 1.80 are ideal. (Maybe this has a lot to do why the 4.0L engines are so long lasting. Their rod ratio is 1.794)

When I was originally researching this topic, it was for my 68 Mustang ----> Insert lame bragging picture here: (Don't mind the skinny-ness. I was 16 at the time.)
mustang68-1.jpg


I was considering stroking a 302 out to a 347. A stock 302 has a rod ratio of 1.696:1 ------- A 347 would put the block at a 1.588:1 ratio. So I actually decided against stroking out the engine because I was more concerned with durability than power. (Actually I went with a 289, but thats a different story. Long story short, I was "persuaded" by my parents to save money for college. And by "persuaded" I mean "Listen to me or else.")
rotfl2.gif


So.....

A stock 4.0L (241.5 cubic inches; 3.875" bore) has a 6.123" rod and a stroke of 3.413" so its rod ratio is 1.794

A stock 4.2L (258 cubic inches, right?) has a 5.875" rod and a 3.895" stroke so its rod ratio is 1.508.

As you already know, most guys who build their own "poor man's" stroker out of the 4.0L get the 3.895" stroke crankshaft from the 4.2L engine. On a 4.0L engine with the stock 6.123" rods and 3.875" bore, the stroker crank increases displacement to 276ci (4.5L). This gives a rod ratio of (6.123 / 3.895) = 1.572.

There are many ways to get around a "bad" rod ratio, but with them comes increased cost. Here's some real good stroker information. Definitely Google around and read up:
Jeep Stroker Motor Information

Jeep Strokers • Dynamic\Static Compression Ratio Calculator

From Junker to Stroker

Whats your buddies stroker putting to the wheels? Or even before drivetrain? The only stroker builds I have seen that don’t run a higher octane are the simplier built ones, not the ATK/Golen ones (Like the ones putting 270hp before flywheel). Don’t get me wrong, I am seriously considering a Golen stroker, but its not the same always hitting 200k tractor engine that came from the factory.
 
  • Like
Reactions: Chris and Forty
OP
Forty

Forty

TJ Enthusiast
Supporting Member
Nov 28, 2016
164
48383
Here is a post from another forum with quite a bit of informantion in it:

Axl Jack 02:01 AM 03-25-2010
I think the only regret somebody would have, if they bought a stroker from a certain re-manufacturer, is if their Jeep is their DD and now have to run higher octane fuel. (Read the fine print on a lot of websites.... says their stroker engines have to run on 92 octane because of the higher compression ratios.) So yeah you're getting a lot more power (and fun), but now not only are you getting worse gas mileage, but you have to fill it up with more expensive fuel!

Quote:
Originally Posted by wendell
JP mag says they haven't seen a stroker get over 20,000 miles on them.
Sometimes stroker's aren't as durable. Now, that's not to say, "Oh my God! A stroker will wear down after 10,000 miles." Let me explain. (Hmmmm, let me do some Googling here.)

Its mostly about rod ratio (rod to stroke ratio). Rod Ratio = (rod length / stroke) This little calculation tells you the motor's rod angularity. A LOW rod ratio means a HIGH rod angle. A high rod angle creates a greater potential for accelerated wear to cylinder walls, pistons, and piston rings (picture an extremely low rod ratio that is driving the piston into the side of the cylinder wall). For example, a motor with a 5.400" rod length and a 3.000" stroke yields a rod ratio of 1.8:1. If we maintain the same stroke and shorten the rod length to 5.000" we get a 1.7:1 rod ratio. The rod angle has increased.

The picture on the left is Low Rod Angle (or High Rod Ratio) and the picture on the right is High Rod Angle (or Low Rod Ratio). The bottom picture is just there as an extra visual aid.

View attachment 26731

View attachment 26732

By lengthening the rod (as stroke is increased) you can offset the increased rod angle. But this requires further shortening of the piston. The further the piston is shortened the more likely the piston pin will intersect the oil ring groove, creating a potential for increased oil consumption.

Basically, there comes a point when you cannot shorten the piston any further before dependability is compromised.

The consensus, from what I've read, among engine manufacturers is that a ratio of 1.50" is the lowest acceptable rod ratio for a street motor. Realistically, rod ratios between 1.65 - 1.80 are ideal. (Maybe this has a lot to do why the 4.0L engines are so long lasting. Their rod ratio is 1.794)

When I was originally researching this topic, it was for my 68 Mustang ----> Insert lame bragging picture here: (Don't mind the skinny-ness. I was 16 at the time.)
View attachment 26733

I was considering stroking a 302 out to a 347. A stock 302 has a rod ratio of 1.696:1 ------- A 347 would put the block at a 1.588:1 ratio. So I actually decided against stroking out the engine because I was more concerned with durability than power. (Actually I went with a 289, but thats a different story. Long story short, I was "persuaded" by my parents to save money for college. And by "persuaded" I mean "Listen to me or else.") View attachment 26734

So.....

A stock 4.0L (241.5 cubic inches; 3.875" bore) has a 6.123" rod and a stroke of 3.413" so its rod ratio is 1.794

A stock 4.2L (258 cubic inches, right?) has a 5.875" rod and a 3.895" stroke so its rod ratio is 1.508.

As you already know, most guys who build their own "poor man's" stroker out of the 4.0L get the 3.895" stroke crankshaft from the 4.2L engine. On a 4.0L engine with the stock 6.123" rods and 3.875" bore, the stroker crank increases displacement to 276ci (4.5L). This gives a rod ratio of (6.123 / 3.895) = 1.572.

There are many ways to get around a "bad" rod ratio, but with them comes increased cost. Here's some real good stroker information. Definitely Google around and read up:
Jeep Stroker Motor Information

Jeep Strokers • Dynamic\Static Compression Ratio Calculator

From Junker to Stroker

Whats your buddies stroker putting to the wheels? Or even before drivetrain? The only stroker builds I have seen that don’t run a higher octane are the simplier built ones, not the ATK/Golen ones (Like the ones putting 270hp before flywheel). Don’t get me wrong, I am seriously considering a Golen stroker, but its not the same always hitting 200k tractor engine that came from the factory.
Wow! That is a lot to consider. Thank you for the info and taking the time to post it. I will reference the links you listed for sure!
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
Wow! That is a lot to consider. Thank you for the info and taking the time to post it. I will reference the links you listed for sure!
To conclude though, I still think its the best upgrade for those with a tired 4.0l. It is my main considerationg for more power as I turn 160k miles on my 4.0. One of my closest jeeper buddies has a 4.6 stroker and its quite nice.
 
  • Like
Reactions: Forty
OP
Forty

Forty

TJ Enthusiast
Supporting Member
Nov 28, 2016
164
48383
Maybe @Johnie Burns will chime in hear, I believe he's got a nice stroker build going on as we speak.

Why are you thinking it needs a rebuild with 54k miles? That's almost unheard of. Is the compression shot or something?

A stroker kit is worth it if done properly and for the right price. You probably will lose a little fuel economy, but only because your foot will be heavier on the pedal.[/QUOT

Yeah the compression is wacky as ever. 1, 3, and 5 are at 130 psi; 2 and 4 are at 100psi; and 6 is at 110 psi.
I had a friend check the pcm and via that the miles are on. Basically the guy I bought it from mudded it and either it was caused by the mud I found caked up in the intake manifold or he was at red line the entire time or he was doing so. It’s the only thing making sense. When I did my rear main I noticed my race bearing and crank were scored really bad.
E651DD77-A7A7-4F8E-A316-6C931B161638.jpeg


0AC97C3B-8146-47AD-8315-0921916EB226.jpeg


D14E430C-7CBE-4F09-90D6-FE1B24B4E55A.jpeg
 

Mike_H

Rust Belt Heavyweight
Supporting Member
Feb 28, 2017
4,302
Grand Rapids, MI, United States
Here is a post from another forum with quite a bit of informantion in it:

Axl Jack 02:01 AM 03-25-2010
I think the only regret somebody would have, if they bought a stroker from a certain re-manufacturer, is if their Jeep is their DD and now have to run higher octane fuel. (Read the fine print on a lot of websites.... says their stroker engines have to run on 92 octane because of the higher compression ratios.) So yeah you're getting a lot more power (and fun), but now not only are you getting worse gas mileage, but you have to fill it up with more expensive fuel!

Quote:
Originally Posted by wendell
JP mag says they haven't seen a stroker get over 20,000 miles on them.
Sometimes stroker's aren't as durable. Now, that's not to say, "Oh my God! A stroker will wear down after 10,000 miles." Let me explain. (Hmmmm, let me do some Googling here.)

Its mostly about rod ratio (rod to stroke ratio). Rod Ratio = (rod length / stroke) This little calculation tells you the motor's rod angularity. A LOW rod ratio means a HIGH rod angle. A high rod angle creates a greater potential for accelerated wear to cylinder walls, pistons, and piston rings (picture an extremely low rod ratio that is driving the piston into the side of the cylinder wall). For example, a motor with a 5.400" rod length and a 3.000" stroke yields a rod ratio of 1.8:1. If we maintain the same stroke and shorten the rod length to 5.000" we get a 1.7:1 rod ratio. The rod angle has increased.

The picture on the left is Low Rod Angle (or High Rod Ratio) and the picture on the right is High Rod Angle (or Low Rod Ratio). The bottom picture is just there as an extra visual aid.

View attachment 26731

View attachment 26732

By lengthening the rod (as stroke is increased) you can offset the increased rod angle. But this requires further shortening of the piston. The further the piston is shortened the more likely the piston pin will intersect the oil ring groove, creating a potential for increased oil consumption.

Basically, there comes a point when you cannot shorten the piston any further before dependability is compromised.

The consensus, from what I've read, among engine manufacturers is that a ratio of 1.50" is the lowest acceptable rod ratio for a street motor. Realistically, rod ratios between 1.65 - 1.80 are ideal. (Maybe this has a lot to do why the 4.0L engines are so long lasting. Their rod ratio is 1.794)

When I was originally researching this topic, it was for my 68 Mustang ----> Insert lame bragging picture here: (Don't mind the skinny-ness. I was 16 at the time.)
View attachment 26733

I was considering stroking a 302 out to a 347. A stock 302 has a rod ratio of 1.696:1 ------- A 347 would put the block at a 1.588:1 ratio. So I actually decided against stroking out the engine because I was more concerned with durability than power. (Actually I went with a 289, but thats a different story. Long story short, I was "persuaded" by my parents to save money for college. And by "persuaded" I mean "Listen to me or else.") View attachment 26734

So.....

A stock 4.0L (241.5 cubic inches; 3.875" bore) has a 6.123" rod and a stroke of 3.413" so its rod ratio is 1.794

A stock 4.2L (258 cubic inches, right?) has a 5.875" rod and a 3.895" stroke so its rod ratio is 1.508.

As you already know, most guys who build their own "poor man's" stroker out of the 4.0L get the 3.895" stroke crankshaft from the 4.2L engine. On a 4.0L engine with the stock 6.123" rods and 3.875" bore, the stroker crank increases displacement to 276ci (4.5L). This gives a rod ratio of (6.123 / 3.895) = 1.572.

There are many ways to get around a "bad" rod ratio, but with them comes increased cost. Here's some real good stroker information. Definitely Google around and read up:
Jeep Stroker Motor Information

Jeep Strokers • Dynamic\Static Compression Ratio Calculator

From Junker to Stroker

Whats your buddies stroker putting to the wheels? Or even before drivetrain? The only stroker builds I have seen that don’t run a higher octane are the simplier built ones, not the ATK/Golen ones (Like the ones putting 270hp before flywheel). Don’t get me wrong, I am seriously considering a Golen stroker, but its not the same always hitting 200k tractor engine that came from the factory.
Don't have any idea of the HP and TQ numbers on my friends engine. Like I said, he bought it that way and while its not his daily, he does drive it a lot. He might know, but I don't think so.
 
  • Like
Reactions: JamesAndTheSahara

ac_

zombicon
Supporting Member
Jun 15, 2017
4,213
AZ, United States
It seems like there is a lot of information here and a lot of technical work.

So here is what I am thinking about your original question with no scientific information. Just thinking this out.
I believe with a stroker, if you do it truly right, you will gain low end on the engine; on one that has a pretty good low end to start with. You will lose some high end. Anytime you make a change good or bad you have to give and take. For every action there is a reaction.

To me these motors are pretty solid. You seem like you have had a bit of bad luck or sabotage. In any case, you have to mess with a motor prematurely. It would definitely be bragging rights, and I would for sure be impressed if you did it, but is it necessary or even going to add value other than bragging rights? You will give up something to gain something, so that gain has to be worth while.

If it was me, I would just do a quality rebuild, and change the oil every time it is needed and be done with with it.

Rebuild the motor close the hood, open the hood change your oil close the hood, drive your Jeep. That is my advice unless you are a gear head and you really want to always be working on your engine. Not saying that you will constantly have to work on it, but if you stroked it. I don't believe you are going to get the same life out of it as you would keeping it stock.

As JamesAndTheSahara said he is running upwards of 160K Miles and I am at 174K, these are proven engines. When it does come time to rebuild mine I will just rebuild to stock.

Now this is just my thoughts and opinions. I don't know you, and if you have the know-how and the means I say go for it, but for me I would just rebuild it stock.
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
It seems like there is a lot of information here and a lot of technical work.

So here is what I am thinking about your original question with no scientific information. Just thinking this out.
I believe with a stroker, if you do it truly right, you will gain low end on the engine; on one that has a pretty good low end to start with. You will lose some high end. Anytime you make a change good or bad you have to give and take. For every action there is a reaction.

To me these motors are pretty solid. You seem like you have had a bit of bad luck or sabotage. In any case, you have to mess with a motor prematurely. It would definitely be bragging rights, and I would for sure be impressed if you did it, but is it necessary or even going to add value other than bragging rights? You will give up something to gain something, so that gain has to be worth while.

If it was me, I would just do a quality rebuild, and change the oil every time it is needed and be done with with it.

Rebuild the motor close the hood, open the hood change your oil close the hood, drive your Jeep. That is my advice unless you are a gear head and you really want to always be working on your engine. Not saying that you will constantly have to work on it, but if you stroked it. I don't believe you are going to get the same life out of it as you would keeping it stock.

As JamesAndTheSahara said he is running upwards of 160K Miles and I am at 174K, these are proven engines. When it does come time to rebuild mine I will just rebuild to stock.

Now this is just my thoughts and opinions. I don't know you, and if you have the know-how and the means I say go for it, but for me I would just rebuild it stock.
I’ve got the itch so I’m screwed, something drastic is gonna happen.
 

ac_

zombicon
Supporting Member
Jun 15, 2017
4,213
AZ, United States
I’ve got the itch so I’m screwed, something drastic is gonna happen.
Nothing wrong with that, in fact I am a huge fan of JamesAndTheSahara! The build thread is like a good book I can't put down.

You are a lot like me years ago, but I was a lot more half hazard than you, and to my defense there wasn't good forums like this back when I was doing this as seriously as you. I like the care and time you take to research everything so you know what to expect and are happy with the results.
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
Nothing wrong with that, in fact I am a huge fan of JamesAndTheSahara! The build thread is like a good book I can't put down.

You are a lot like me years ago, but I was a lot more half hazard than you, and to my defense there wasn't good forums like this back when I was doing this as seriously as you. I like the care and time you take to research everything so you know what to expect and are happy with the results.
I appreciate that!
 
  • Like
Reactions: ac_

Dozerdude

Member
Aug 13, 2016
87
If you live in Highland stop by LaFontaine Performance Center in the old bowling lanes on Milford Rd and talk to them about a crate motor. It will be more money but more performance also. Good luck!
 
  • Like
Reactions: Forty and ac_
Im getting in this late but give Russ Pottenger on jeepstrokers.com a call and tell him what you want and he will give you what you can expect from a mild stroker build to the one I was going to build hitting right at 400hp. He has built a ton of them so theres more fact then opinion. He has even forged his own pistons because of what he saw was needed by building them. I put a salvaged 4.0 motor in my 2000 TJ I bought with a locked up 4.0 in July and my life changed and so did my opinions. I love driving my Jeep, alot, I mean alot. I like spinning the tires, popping wheelies, (up hills of course,) and jumping her! Duh, I break chit! Lol. If it breaks doing what I do then it was meant to be upgraded so it wont. But on a simple note, the 4.0 sucks at highway speeds. I spent 1100 bucks for a solid 4.0 with a year warranty. And it sucks at highway speeds. I want and need more power but not 400hp and have to keep adjusting lifters. I want bulletproof and impressive passing power at highway speeds. Ive got all the crawling power I need with the stock 4.0. You can keep it under 3 grand, Im not because I chose to put money in my engine build like it was a monthly payment for a new Jeep. And thats where any build has its meaning, what do YOU want? When you know you will be happy. Get real facts from people who have done it. Me personally if Im going through the hassle of pulling it and going through her then Im making solid upgrades that make me happy and give me bragging rights others dont have! Well thats my 2 cents, Merry Christmas everybody!
 

JamesAndTheSahara

TJ Addict
Supporting Member
May 22, 2017
2,164
Auburn, AL, United States
....... give Russ Pottenger on www.jeepstrokers.com a call and tell him what you want and he will give you what you can expect from a mild stroker build to the one I was going to build hitting right at 400hp. He has built a ton of them so theres more fact than opinion. .......
But on a simple note, the 4.0L sucks at highway speeds.
I want and need more power but not 400hp .....
I want bulletproof and impressive passing power at highway speeds. Ive got all the crawling power I need with the stock 4.0L. .....
Agree with you Mr. Burns ..... the 4.0L is a slug on the highway.
As I've mentioned before, a GM '292' inline 6 would be an interesting implant.
My '02 Dodge/Cummins 4x4 dyno's out at 315hp & 710tq ..... so jumping into the TJ for a highway trip is less than impressive, and add to that .... it gets poorer mileage at 20+ mph slower speed, while burning a more expensive fuel.
Reality is .... the 4.0L is anemic in stock form.
 
  • Like
Reactions: Johnie Burns